Casing pump for oil wells and the like



HUBERTl D. COLLINS x Y ATTORNEYS g i i V412l! lNvENToR* Filed'llay 22,1949 H. D. COLLINS CASING PUMP VFUI- OIL WELLS' AND THE LIKE iN nPatented June 3, 19,41

UNITED `STATES PATENT OFFICE CASIN G PUMP FOR OIL WELLS AND THE LIKEHubert D. Collins, Tulsa, Okla..

Application May 22, 1940, Serial No.' 336,501

(Cl. S- 221) 3 Claims.

This invention relates to new and useful improvements in pumpingmechanisms for flowing oil wells and the like. It deals particularlywith well pumps of the type known as casing pumps, which are located inplace inside of the usual well casing and make use of the casing forconducting oil to the `ground surface.

A desirable type of casing pump construction, as employed heretofore inoil well flowing operations, includes a working barrel for the pumppiston, an expansible packer of rubber composition or vthe likeconnected through a drain sleeve with the working barrel, a pumpheadcarrying a mandrel that is movable into the packer to expand thesame into sealing engagement'with the well casing, a drain tubedepending from the mandrel toward the working barrel, and the usualstring. of sucker rods connected with the piston. The pump mechanism islowered intothe well casing by the sucker rods, and when it reaches thedesired pumping position (after having been located in place by suitablemeans provided for that purpose) the mandrel is moved into the packer toseal the pump in the well.

Thereafter, the sucker rods are reciprocated to move the piston in theworking barrel and thus force oil upwardly through the working barrel,the drain tube, the pump head and the well casing.

type from the well, it is necessary to lift the mandrel out of thepacker so that the seal between the latter and the well casing may bebroken. The column of oil lying between the pump proper and the groundsurface, however,

' still bears on the packer and hinders withdrawal of the pump. It willbe understood that a large amount of oil is held in the casing of a deepweil, so that the hydrostatic pressure may be very great. Although ithas been proposed to overcome the attendant diilculties by providingdrainage ports below the packer, this expedient is of limitedeilectiveness due to the restricted space which may be available, theresilient or flexible construction of the packer and the highhydrostatic pressures that may prevail.

Y It is therefore the object of this invention to provide a new andimproved casing pump construction which equalizes hydrostatic pressureon the packer and gives positive drainage of liquid through the pumpitself after the mandrel has been unseated, thereby increasing theemciency of the pump while retaining all of the desirable features ofthe aforesaid known type of' pump construction.

When it is desired to remove a pump of this Other objects and advantagesof my invention will be apparent from the following detailed descriptionof a preferred embodiment thereof, when considered in connection withtheaccompanying drawing, in which Figure 1 and Figure 1a are longitudinalviews. partly in cross section, showing, respectively. upper and lowerportions of an illustrative pump mechanism as located in a wellcasingvwith the packer unsealed;

v Figure 2 is a transverse cross section substantially along line 2-2 ofFigure 1;

Figure 3 is a transverse cross section substantially along line 3--3 ofFigure 1; and v Figure 4 is an enlarged longitudinal cross sectionshowing part of the mechanism of Figure 1 with the packer sealed againstthe well casing, as when the pump is ready for operation.

I have found that the eiiiciency of casing pumps may be improved andthat diiilculties incident to the withdrawal of such pumps from oilwells may be substantially reduced by providing the pump with means foreffecting positive well; but when the mandrel is raised out of thepacker to break the seal between the latter and the casing, a newarrangement of drainage facilities comes into operation which givespositive drainage of liquid from the drain tube and avoids theobjectionable pressure conditions and the ineilicient drainage that havebeen characteristics of known casing pump constructions.

The new pump construction is illustrated in Figures 1 and la as theparts are associated when the pump is ready to be sealed in the well,casing I 0, or to be withdrawn from the casing after the completion ofpumping opera.- tions. A pump rod I2 extending into the pump isconnected with the usual string of sucker rods (not shown), or theequivalent. 'I'he lower end of the pump rod (Figure 1a) is connected toa pump piston or sucker Il which carries a travelling valve I6 andsealing rings or gaskets I8 and which is reciprocable by rod i2 in aworking barrel 20. A valve housing 22 at the lower end of the workingbarrel encloses a standing valve 24 through which oil is admitted fromthe well into the working barrel on the upward stroke of piston Il.

An expansible packer l0, of rubber or other similar resilient material,is located near the upper end of the pump and is connected with theupper end of the Working barrel 20 by tubular means including, in theillustrated form, a flanged ring 32, a. drain sleeve 34 and suitabletubular coupling sleeves 36 and 38. The packer 30, as shown in Figure 1,is normally spaced inwardly from the inside surface of the well casingI0. Above the packer and surrounding rod I2 is a pump head 48 whichterminates at its lower end in a mandrel 42 having a tapered camsurface. The head 40 provides a hollow space 44 surrounding the pumprod, which space communicates with the well casing above the packerthrough lateral ports 46. The mandrel 42 is adapted to enter packer 30and to force the same into sealing engagement with the casing I0, asshown in Figure 4. Depending from mandrel 42 in spaced relation to thepump rod I2 is a drain tube 48, which is of such length as to extendsubstantially to the working barrel 23 when the pump is located andsealed in operating position. It will be observed that the drain tube 48extends downwardly from mandrel 42l inside of the packer 30 and insideof the tubular means 32, 34, 36 and 38.

As shown in Figures 1, 3 and 4, cooperating means are providedon draintube 43 and drain sleeve 34 for limiting axial movement of the mandrelrelative to the`packer. In the illustrated form, such means includesspaced recesses or slots 50 in sleeve 34 and fitting tongues or lugs 52,on drain tube 48, which are movable vertically to a limited extent inthe slots 50. At a location above slots 50, the drain sleeve 34 carriesa sealing ring or packing 54 which engagesthe outer wall of thedraintube 48 and prevents entrance of liquid into the underlyingintervening space. Further sealing means are provided between the draintube 48 and the aforesaid tubular means, in the form of a packing ring56 that is located in an annular recess between sleeves 36 and v38 inposition to engage the outer surface of the drain tube. The pack-y ing56 is preferably a chevron packing.

In accordance with this invention, as shown in Figures 1, 2 and 4, thetubular means connect-v ing the packer 30 with the Working barrelii'nthis instance at sleeve 36), is provided above the packing ring 56 witha series of radial drainage ports 60 which lead from the inside ofsleeve 36 to the annular space between the outer surface of sleeve 36and the well casing I0. For' cooperation with these drainage ports 60,the drain tube 48 also Iis provided with a series of radial drainageports 62. As shown in Figures l, these ports 62 are so located that whenthe tongues 52 are positioned near the upper ends of their respectiveslots 50, thatis, when the pump head 40 and mandrel 42 have beenwithdrawn from the packer 30, the ports 62 of the drain tube registerwith the ports 60 of sleeve 36 and thus provide openings for positivedrainage of liquid from the drain tube through the same and sleeve 60and into' the surrounding space of the well casing. When, however, thepump head and mandrel are moved downwardly to a position sealing packer30 against the casing I8, the drainage ports 62 of the drain tube passdownwardly to a position below the packing 56. This position of thepump, which corresponds to the operating position, is shown in Figure 4.It will be understood that the packing 56 then serves to block ow ofliquid from ports 82 to ports 60 and that the pump. when so assembledand operated, causes liquid to be forced upwardly through the workingbarrel, the drain tube, the pump head and the well casing withoutleakage or loss of pressure.

In the use of the new pump construction, the pump is lowered into thewell casing by a string of sucker rods in the usual manner, mandrel 42being spaced from packer 38 with tongues 52 at the upper limits of slots50, as shown in Figure 1. When the pump has reached the desired pumpl0ing position, it is located in place either by resting upon a suitablepreformed obstruction or by the use of a suitable anchoring device ofconventional construction (not shown). The weight of the working barrelassembly is then removed from the tongues 52, and upon further downwardmovement ot the rods the tapered mandrel 42 moves into packer 30 andseals the same against the casing. In this position, as shown in Figure4, the drain tube 48 also is sealed with respect to the surroundingtubular means 32, 34.

rel 26 through standing valve 24, and from the working barrel the liquidis forced through travelling valve I6 and upwardly through the draintube, pump head and well casing.

Upon termination ot pumping operations, the

pump assembly may be removed from the Well by lifting the pump rodsabovey their normal working position so that certain lugs I3 on rod I2strike the upper part 'of head 40. Further lifting of the rods raiseshead 48 and drain tube 48 and forces mandrel 42 out of packer 30,allowing the seal between the packer and the well ycasing to be broken.As the drain tube moves independent of the working barrel assembly untilthe tongues 52 reach the upper limits of slots 50, the drainage ports 62of the drain tube pass above packing 56 and thereupon establish directcommunication between the inside of the drain tube and the surroundingcasing through the drainage ports 60 in sleeve 35. This positivedrainage o1' liquid from the drain tube equalizes hydrostatic pressureon the packer and effects a `comparatively napid drainage of liquid fromthe pump, thereby permitting the pump readily to be withdrawn from thewell and avoiding difliculties that have been encountered heretofore.

As shown in Figures 1 and 4, the drain sleeve 34 may include drainageports 'I0 at a point located above the sealing'ring 54. These ports mayaccommodate a certain amount of drainage inside the packer 30 after themandrel has been unseated, according to known practice.

While I have illustrated and described details of a particularembodiment of my invention, I understand that the invention may beembodied in other forms of construction without restriction to theseparticular details. I therefore desire that the invention be accorded ascope comi mensurate with its novel contributions to the art, asintended to be set forth in the appended claims.

I claim:

l. In a well pump, a working barrel having a standing valve adjacent itslower end and a piston with travelling valve reciprocable therein bymeans of a suitable pump rod. an expansible paoker and said tubularmeans, drainage means opening through the wall of said tubular means;r

sealing means between the drain tube and the tubular means below saiddrainage means, and

drainage means opening through the wall of said drain tube, thelast-recited drainage vmeansA being located below said sealing meanswhen vthe mandrel is positioned within the packer and above said sealingmeans when-the mandrel is withdrawn from the packer.

2. In a well pump including a working barrel,

a -pump piston reciprocable in the barrel by a suitable pump rod, anexpansibie packer con-j nected with the upper end of said `working'bar-A rel by intermediate tubular means, a mandrel.n movable into saidpacker for expandingv thefsame'* into sealing engagement with aw'ell-casiifrg,'andr a drain tube depending from theman'drel into said tubularmeans, cooperating mean's'onv saidv drain tube and `said tubular means`tnrlimiting axial movement of the mandrel relative tothe Y, packer,liquid drainage ports in the wall oi vsaid tubular means, sealing meansbetween'rsaid vdrain and liquid drainage ports in the wall of said draintube, said last-recited ports being located below said sealing meanswhen the mandrel is positioned within the packer and above said sealingmeans when the mandrel is withdrawn from the packer. i

3. In a well pump having a mandrel, a drain tube depending from themandrel. tubular means surrounding the drain tube and an expansiblepacker carried by the upper, end of said tubular means to be expandedinto sealing engagement .with a well casing by downward movement of saidmandrel. `cooperating tongue and slot means on said drain tube andtubular means for limiting axial movement o1' the former relative tothel latter, radial drainage ports in said tubular means below saidtongue and slot means, sealing means between said tubular means and saiddrain tube below said drainage ports. and radial drainage ports in saiddrain tube positioned to register with the aforesaid drainage ports whensaid mandrel is located above said packer.

tube and said tubular means below said ports,J

HUBERT D. COLLINS.

